Sustainable Energy – Without the Hot Air

David MacKay’s Sustainable Energy – Without the Hot Air is a remarkably engaging book; it has certainly kicked off and contributed to some very energetic discussions here. The book, which was written by a physics professor at Cambridge and is available for free online, is essentially a detailed numerical consideration of renewable forms of power generation, as well as technologies to support it, and to reduce total power demand. MacKay concludes that the effort required to produce sustainable energy systems is enormous, and that one of the most viable options is to build huge solar facilities in the world’s deserts, and use that to provide an acceptable amount of energy to everyone.

The book has a physics and engineering perspective, rather than one focused on politics or business. MacKay considers the limits of what is physically possible, given the character of the world and the physical laws that govern it. Given that he does not take economics into consideration much, his conclusions demonstrate the high water mark of what is possible, with unlimited funds. In the real world, renewable deployment will be even more challenging than it is in his physics-only model.

Here are some of the posts in which the book has already been discussed:

I have added relevant information from the book to the comment sections of a great many other posts, on everything from wind power to biofuels.

Even if you don’t agree with MacKay’s analysis, reading his book will provide some useful figures, graphs, and equations, as well as prompt a lot of thought. It is certainly one of the books that I would recommend most forcefully to policy makers, analysts, politicians, and those interested in deepening their understanding of what a sustainable energy future would involve.

There is “no danger” of mass power cuts in the UK during the next decade, Energy Secretary Ed Miliband has said.

He told the BBC it was possible to meet the country’s energy needs while using more “sustainable” sources such as wind farms and nuclear stations.

Last week the government’s new energy adviser warned that the UK could face blackouts by 2016 as green energy is coming on stream too slowly.

But Mr Miliband said building projects would be completed in time.

Cambridge University researcher David MacKay, who takes up his post as adviser at the Department of Energy on 1 October, has warned that the public will keep objecting to facilities such as wind farms and nuclear power stations being constructed near their homes.

“Last year, the Danish island of Samso (pronounced SOME-suh) completed a 10-year experiment to see whether it could become energy self-sufficient. The islanders, with generous amounts of aid from mainland Denmark, busily set themselves about erecting wind turbines, installing nonpolluting straw-burning furnaces to heat their sturdy brick houses and placing panels here and there to create electricity from the island’s sparse sunshine. By their own accounts, the islanders have met the goal. For energy experts, the crucial measurement is called energy density, or the amount of energy produced per unit of area, and it should be at least 2 watts for every square meter, or 11 square feet. ‘We just met it,’ said Soren Hermansen, the director of the local Energy Academy, a former farmer who is a consultant to the islanders.”

Could the world get to 100 percent renewable energy by 2030? Not a chance, say most analysts.

But in an article last month in Scientific American, two California academics outline a path to this amount through “millions of wind turbines, water machines and solar installations.”

The paper, by Mark Jacobson, a professor of civil and environmental engineering at Stanford University, and Mark Delucchi, a research scientist at the Institute of Transportation Studies at the University of California, Davis, envisions 3.8 million large wind turbines, accounting for just over half of electricity demand in 2030. These would be augmented by 90,000 solar plants and other renewable technologies like tidal and geothermal power.

The turbines “would occupy about 1 percent of the earth’s land, but the empty space among turbines could be used for agriculture or ranching or as open land or ocean,” the paper states. Solar plants (not counting rooftop installations) would take up 0.33 percent of the earth’s land.

This is why I think MacKay’s book is so valuable, because of news stories like this:

“Nearly all the energy we use on this planet starts out as sunlight that plants use to knit chemical bonds. Now, for the first time, researchers at the Massachusetts Institute of Technology have created a potentially cheap, practical artificial leaf that does much the same thing—providing a vast source of energy that’s easy to tap. The new device is a silicon wafer about the shape and size of a playing card coated on either side with two different catalysts. The silicon absorbs sunlight and passes that energy to the catalysts to split water into molecules of hydrogen and oxygen. Hydrogen is a fuel that can be either burned or used in a fuel cell to create electricity, reforming water in either case. This means that in theory, anyone with access to water can use it to create a cheap, clean, and available source of fuel.”

Even if your artificial leaf is 100% efficient at turning sunlight into electricity, you would need to cover an enormous area with them to meet today’s energy demand.

Most journalists seem to have no appreciation for scale, when it comes to energy. Yes, you can make biofuel out of discarded fry-cooking oil from fast food restaurants, but that isn’t a technology that scales cheaply to replace gasoline…

There is no easy way to cut the necessary emissions. We do need to be green, but it is not nearly as simple (or as cheap) as the greenies would have you believe. What is required are big changes in demand, and big changes in supply. We’re talking countrywide scales — hundreds of thousands of wind turbines, thousands of square kilometres of solar panels, massive cuts in demand, wholesale switches in technology, gigantic investments. You won’t hear these numbers from politicians, or not very often. Nor will you hear them from business leaders. And hardly ever from environmentalists.

Here are a few lamentable numbers to remember:

Every year our global civilization digs up, transports, heats and pummels and shapes and processes and sells half a trillion tons of materials. Only six per cent of all those tons ends up in products — the rest is used to mine and make and move them. And only one per cent — a single measly per cent — is still a useful product six months later.

Only 37 per cent of primary energy production is put to any real use. The rest is lost to conversion inefficiencies and waste.

About four-fifths of all energy used in transportation, including trains and planes, is spent on road traffic — and about half of that is for moving light vehicles and people. Worse, only about five per cent of the energy we expend in transportation actually gets us from one place to another. The rest is just to shift our inefficient internal combustion vehicles or is sent out the tailpipe as waste heat. Ninety-five per cent of the energy we use to get to Wal-Mart is wasted. So much for so-called “savings.”

The International Energy Agency estimates that somewhere around $45 trillion, or an average of one per cent of annual global economic output, needs to be invested between now and 2050 to make any real difference — which sounds unlikely in this era of “jobless recoveries” and multiple fiscal crises.

The International Energy Agency is notoriously conservative on projections for renewable energy. The agency has embraced the need for more clean electricity and fuels to address climate change and peak oil, but its outlook for the future is usually far more conservative than how reality plays out.

So when an official at the IEA says we could get up to one third of our global energy supply from solar photovoltaics, concentrating solar power, and solar hot water by 2060, that’s a fairly big piece of news. But even that projection may be conservative.

In December 2011, DECC published the Carbon Plan and version 3 of the 2050 Pathways Calculator.

As before, this open-source engineering-based tool is intended to support grown-up conversations about our possible energy futures. The user can choose any combination of demand-side and supply-side actions over the period to 2050, and the calculator computes and displays various consequences – energy flows, areas of land use, greenhouse gas emissions, and some security-of-supply indicators. The significant new feature in version 3 is the inclusion of costs, for the first time. Version 3 of the calculator also includes an air-quality calculator, which, like the costs calculator, is under development. Expert feedback is welcome.

Germany’s energy transformationEnergiewende
German plans to cut carbon emissions with renewable energy are ambitious, but they are also risky

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The micro-level works almost too well. Schleswig-Holstein plans to generate three times as much renewable energy as it consumes and to export the surplus south and west. Southern states are keen to produce their own renewable power, too. Bavaria talks of self-sufficiency. The states’ windpower targets add up to double the federal government’s goal of 36 gigawatts by 2020.

Enough Wind to Power Global Energy Demand: New Research Examines Limits, Climate Consequences

ScienceDaily (Sep. 9, 2012) — There is enough energy available in winds to meet all of the world’s demand. Atmospheric turbines that convert steadier and faster high-altitude winds into energy could generate even more power than ground- and ocean-based units. New research from Carnegie’s Ken Caldeira examines the limits of the amount of power that could be harvested from winds, as well as the effects high-altitude wind power could have on the climate as a whole

Oct. 16, 2013 — Researchers at the UPM have found that real contribution to emissions targets is positive even in energy markets with high penetration of wind energy.

The finding has generated the first comprehensive analysis on interaction between wind parks and thermal power plants in Spain and has concluded that global balance of CO2 reduction is still significant. Besides, the study suggests how to enhance effectiveness of potential sources that can be helpful for promoters of renewable technologies.